Actually, looking at RasterIO calls, I see that the first ones are done with large source windows, and involve (nearest neighbour) downsampling on GDAL side. e.g. RasterIO(band=1,5208,0,5228,5228,bufxsize=1026,bufysize=1026). Later calls are done on 165x165 windows and don't involve downsampling on GDAL side.
This is odd to me and worth a closer look. My assumption was that because tilelive-bridge is requesting 512x512 tiles from node-mapnik and because buffer-size:0 for the layer and filter-factor is 2 the window requested of GDAL should be 1024x1024.
@rouault noticed:
This is odd to me and worth a closer look. My assumption was that because tilelive-bridge is requesting 512x512 tiles from node-mapnik and because
buffer-size:0for the layer and filter-factor is 2 the window requested of GDAL should be 1024x1024.